Process of making photographic masks



July 21, 1925.

E. E. HOTTMAN PROCESS OF MAKING PHOTOGRAPHIC MASKS Filed March 27, 1922Patented July 21, 1925.

UNITED STATES EMIL E. HOTTMAN, OF CHICAGO, ILLINOIS.

PROCESS OF MAKING PHOTOGRAPHIC MASKS.

Application filed March 27, 1922. Serial No. 547,127.

To all whom it may co'ncem:

Be it known that I, E-MIL E. HorrMAz a citizen ofthe United States, anda resident of the city of Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in a Processof Making Photographic Masks; and I do hereby declare that the followingis a full, clear, and exact description of the same, reference being hadto the accompanying drawings, and to the numerals of reference markedthereon, which form a part of this specification.

This invention relates to masks such as are used in covering a portionof a pieceof photo-printing paper to enable the remaining portion to beprinted separately.

It is an object of thls invention to prepare such a mask which shall bemore convenient to handle than the paper or metal masks heretofore used,and which shall afford a greater variety of gradations of light andshade in the border.

It is a further object of this invention to devise a method by which amask may be prepared for reproducing any particular style or kind ofborder or deslgn including those which have black, white and1ntermediate shades, as Well as those having only the one contrast.

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.

The invention (in a preferred form) is shown on the drawings andhereinafter more fully described.

On the drawings:

Figure 1 is a broken view showing one corner of a form having a borderto be produced.

Figure 2 is a broken v1ewi showing one corner of the mask made fromFigure 1.

Figure 3 is a view showing the entire mask superposed upon the printingpaper.

Figure 4. is a view illustrating a mask superposed on the printingpaper.

Figure 5 is a view of the finished picture.

'As shown on the drawings:

The desired border or reproduction may be any design or configurationdesired. For the purposes of illustration, a border is chosen having anoutside black line 1, next to which there is a white marginal space 2,which is followed by a shaded portion 3, the darkest part of which is atthe outer edge. This is followed by a curved shaded portion 4, thelighter part of which is at the outer edge. At the corners of the borderthere is a white space 5 between the lighter edges of the two shadedortions. The curved shaded portion 4 is intended to inclose a space (iwhich is to receive the picture.

In the practice of this invention, the cardboard or other white surfacecontaining the border shown in Figure 1 is photographed and the negativeresulting is developed. This will consist of an outer white line 1representing the black line 1 in Figure 1, followed by a black band 2representing the white band 2. This is followed by a shaded portion 3,the lightest part of which is toward the outside corresponding to theshaded portion 3 in Figure 1, which has its darkest edge toward theoutside. Within this is a curved shaded portion 4 with its lightest parttoward the inside corresponding to the shaded portion 4 in Figure 1,which has its darkest edge toward the inside. Within this is the solidblack portion 6 corresponding to the solid white portion 6 of Figure 1.

The portion 6 should have the greatest degree of opacity possiblebecause it is to completely protect the central portion of the print inmaking the picture. The opacity should be of such a density as to fullyprotect the portions of the sensitive material of whatever kindselected, that in the exposures necessary to produce the border, tintsor designs there will have been no actinic action of the light on theportions which it is desired to protect. If the desired degree ofopacity cannot be obtained in the region 6 by photographing thecardboard or other surface containing the border shown in Figure 1, theplate which is to make the negative shown in Figure 2 is covered by amask such as shown at 20 in Figure 4, and exposed through the opening ofthis mask to any source of light. The necessary registration between themask 20 and the latent image upon the plate is secured by an of themeans with which Workers in this art are familiar.

When the border shown in Figure 1 has been photographed and the centralportion of the negative additionally exposed if required, the plate isdeveloped and the result is the negative shown in Figure 2. Outside ofthe border line 1' this negative has a strip 7 of black made by thelight which comes around the edge of the cardboard shown in Figure 1 oris reflected from the surface of such cardboard extending beyond theborder line 1 in Figure 1. Outside of the strip 7 the negative shown inFigure 2 will have a strip 8 which Will be substantially transparent andwhich results from that portion of the plate which was protected fromlight by the device which kept the plate in place during the exposure.The negative thus prepared is designated by the numeral 10.

Having prepared this negative or mask 10, the next step is in its use inmaking a photographic print as illustrated in Figure The negative 10 isplaced on top of a piece of paper or other material 11 which issensitized to receive the print and the two placed in a printing frameor other suitable device and exposed to light. The result is to impartto the print a border. If the sensitive material is of the printing outvariety, this border will show when the negative 10 is removed from thesensitive paper 11. If a developing paper is used, the image of theborder will be latent.

The next step in the process of making the print is illustrated -inFigure 4. The border, which has been printed upon the sensitive material11, is covered by a mask 20 of a shape and size to completely cover theborder but leave the central portion of the print wholly exposed. Thismask 20 may be of metal or paper-cut to the desired shape, or it may bea negative plate made by exposing a plate to any source of light andhaving the central portion thereof covered by a protector or mask of ashape and size corresponding to the space 6 or 6. Another way of makingthe mask 20 is to take a plate that has been exposed all over and removethe coating from the part that is to be transparent. The plate may bedeveloped either before or after such removal. The coating left on itwill of course be opaque when developed. The mask 20 may be applied tothe sensitive paper 11 directly as shown in Figure 4 and a negative of apicture superposed upon the mask 20, but preferably the negative of thepicture is placed between the mask 20 and the sensitive paper 11. I Thenecessary registration between the mask 20 and the image of the border,whether the image is visible on the print or not, is secured by meanswith which photographers are famillar.

The resulting print is shown in Figure 5. It is on the sheet 11 of paperor other material and has a border beginning with the outer line 1 andrepeating the pattern shown in Figure 1 as far as the inner curved band4, including the corner spaces 5, and has within the border 4 a picture30, corresponding to the negative used with the mask 20 in Figure 4.

Although I have represented a border inclosing a curved edge for apicture, it is obvious that the same method may be used for pictures ofother shapes having margins made of straight or broken lines or of othercurves, as desired. The method is also useful for dividing the centralspace into subspaces to receive dilferent pictures.

I am aware that numerous details of construction may be varied through awide range and that numerous details of procedure in the process may bechanged to a large amount without departing from the spirit of thisinvent-ion, and I therefore do notpurpose limiting the patent grantedotherwise'than necessitated by the prior art.

I claim as my invention:

1. The method of making a photographic mask having an opaque centralportion and a marginal portion containing translucent portions whichincludes photographing a white surface surrounded by the desired borderand using a longer exposure for the white surface than for the border.

2. The method of making a photographic mask including photographing awhite surface surrounded by the desired border, the border being coveredby a mask during a portion of the exposure.

In testimony whereof I have hereunto subscribed my name in the presenceof two subscribing witnesses.

EMIL E. I-IOTTMAN.

- 'VVitnesses:

CARLTON HILL, JAMES M. OBRIEN.

